This invention relates to a method and an apparatus for correcting a position of a cut edge of a belt-shaped member, for example, carcass ply, belt layer or the like for constituting a tire to be produced into a required configuration of the cut edge, while a cut edge portion of the member is held.
An example of prior art apparatus for holding a cut edge portion of a belt-shaped member is illustrated, for example, in Japanese Patent Application Laid-open No. 64-16,630 proposed by the assignee of this application. Moreover, an example of prior art apparatus for correcting an extending direction of a cut edge of a cut edge portion which is held by suction is also illustrated, for example, in Japanese Patent Application Laid-open No. 64-30,738 proposed by the assignee of this application.
With the former disclosed holding apparatus, holding pawls are pivotally connected to both forward and rearward surfaces of a holding member extending in the width direction of a belt-shaped member and rockable about the pivoted axes with the aid of cylinders. A cut edge portion of the horizontally lying belt-shaped member is folded upwardly between the holding member and the holding pawl by an action of a bending member upwardly moving in the vertical direction. The holding pawl is then rocked to embrace the end of the belt-shaped member between the holding pawl and the holding member. In the latter disclosed correcting apparatus, grasping means are magnetically attracted to a cut edge therealong of a belt-shaped member reinforced by steel cords and in this condition the cut edge portion thereof is somewhat raised. Thereafter, the grasping means are rotated in a horizontal plane in a desired direction through a required angle by means of driving means comprising a motor and a gear mechanism so that the direction of the cut edge of the belt-shaped member is correct to a desired direction with the aid of a plasticity of the raised portion of the belt-shaped member.
Among such prior art apparatus, the former holding apparatus can hold cut an edge portion of a belt-shaped member without damaging the held portions. Moreover, with the latter correcting apparatus, a substantially straight cut edge of a belt-shaped member inclined at a constant angle to a predetermined reference straight line can be brought into a direction sufficiently close to the reference straight line.
In general, cut edges of belt-shaped members are not necessarily straight. The cut edges are often curved or wave-shaped, which were affected by embedded reinforcing cords such as steel cords or the like. However, both the prior art holding and correcting apparatus could not correct unevenness of such curved or wave-shaped cut edges. The prior art correcting apparatus can only bring an approximate straight line assumed from an uneven cut edge into a position close to the reference straight line. Therefore, in a case that front and rear edge portions of a belt-shaped member wound around a forming drum are lap-joined, overlapped amounts of the front and rear edge portions could not be uniform in the width direction of the belt-shaped member. In the case of butt-joined, moreover, the front and rear edge portions could not be butt-joined without any clearances along the entire width of the forming drum. Therefore, a problem of lower uniformity of produced tires arises with such difficulties.